FIGS. 1a-c illustrate examples of prior art powder metal components having holes formed in directions orthogonal to the direction of pressing. Typically, but not always, the direction of pressing is vertical. Therefore, the holes in FIGS. 1a-c would be running with their axes horizontal when being vertically pressed. The use of “vertical” and “horizontal” as used herein is not intended as limiting in orientation, only to communicate that the two directions are orthogonal to one another, or that “horizontal” is orthogonal to the direction of pressing, regardless of whether the direction of pressing is aligned with the direction of gravity or not.
Component 10 in FIG. 1a, component 15 in FIG. 1(b) and component 20 in FIG. 1c represent three of many possible configurations of metal components where the final component requirements dictate the necessity of horizontal holes or slots through the part. In prior methods of producing a powder metal component, the requirement for horizontal holes or slots required additional processes to form the hole or slot. Common prior methods of providing horizontal holes or slots in powder metal components added additional manufacturing processes, known as secondary manufacturing processes, to form the holes or slots. These additional manufacturing processes included drilling, punch piercing or cutting by milling, heat deformation cutting, plasma cutting or other hole or slot forming metal removal processes.
There are several disadvantages to the previous processes of hole or slot creation in powder metal components. These include the additional capital equipment and expenditure required for the additional manufacturing step, the additional time required for completing the added manufacturing step, the added risk one or more holes or slots are missed in being created during the secondary process, the additional handling and storage required in the secondary processes, the scrap that is created from the secondary processes, and the additional labor and maintenance costs involved with the secondary processes.
The cost of the additional processes required to produce the holes or slots often would make the powder metal process for forming the part cost prohibitive. The parts might not even be quoted due to the necessity of these features. Unfortunately this resulted in the loss of many of the advantages of components being produced by the powder metal process, such as the ability to produce complex shapes with close tolerances.